“- noun
Etymology: Middle English ymber day, embyr day, from Old English ymbrendæg, from ymbryne, ymbrene circuit, course, anniversary (fr ymb, ymbe around + ryne course, running, period of time) + dæg day; akin to Old High German umbi around, Old Norse um, umb, Greek amphi, and to Old English rinnan to run — more at by , run , day
: a Wednesday, Friday, or Saturday in any of the four weeks commencing on the first Sunday in Lent or on Whitsuntide or including or immediately following September 14 or December 13 set apart for fasting and prayer and observed especially by the Anglican and Roman Catholic Churches